Impact of food production and consumption is the main theme of the U.N. IPCC's new report.

A much-anticipated international climate report summary out Thursday carries a critical warning for people and corporations alike: Both individual and collective action will be required in order to stave off the worst impacts of climate change.

The sweeping report from the United Nations Intergovernmental Panel on Climate Change (IPCC) focuses on land use, with an emphasis on farming, forestry, and agriculture. Examining the link between land use and global warming, the report finds the world on a collision course. As the need for zeroing-out emissions grows more critical for addressing climate change, food security and land degradation are also emerging as a major problem, one exacerbated by global warming.

Along with forestry and other land uses, agriculture accounts for 23% of global greenhouse gas emissions, the report states. Cattle and rice fields alone are responsible for roughly half of all methane emissions. And agricultural practices have largely contributed to soil degradation, furthering global food insecurity. Meanwhile, the report states that between 25% and 30% of all food goes to waste, spurring greater emissions (for example, due to methane released from landfills).

While reducing emissions associated with fossil fuels is key to mitigating the impacts of climate change, the new report homes in on changes big and small — from personal habits to systemic shifts — that will be necessary to truly address climate change.

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That means an overhaul of forestry and agriculture, but it also means shifting human diets and expectations. The recommendations come at a time when some U.S. lawmakers, including several Democratic presidential contenders, are looking to overhaul national farming practices with an eye toward climate action.

“Something very new in the report really was to take a look at the food system as a whole from the production side, from the supply chain side,” Cynthia Rosenzweig, a NASA senior research scientist and IPCC lead author, said in a statement. “How does the food get to [people], and what kind of greenhouse gas emissions are associated with transport and packaging, and retail, and storage. All of those also provide opportunities for reduction in greenhouse gas emissions.”

Among the necessary changes recommended in the report is producing more food on less land, doing so more sustainably, and both wasting less food and changing what people eat. While the IPCC does not directly instruct a full shift to vegan and vegetarian diets, the report is relatively blunt about the need for a decrease in meat consumption and an embrace of more plant-based diets. Those diets are less resource-intensive and associated with fewer greenhouse gas emissions.

Climate advocates have long disagreed over the role to which individual action can help to combat global warming, with collective change from fossil fuel companies, for example, often cited as a more important effort. But the IPCC report indicates that both will be necessary in order to combat the climate crisis.

In a statement, Pamela McElwee, an IPCC lead author and ecology professor at Rutgers University, argued the upside of such conclusions. “One of the important findings of our work is that there are a lot of actions that we can take now,” she said. “They’re available to us now.”

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But serious hurdles remain. For example, as bioenergy sources like ethanol become more critical, they can cause further land degradation as they take up space and water resources while infringing on biodiversity. Planting more trees, meanwhile, is likely a necessity to absorb carbon, but that practice can worsen livestock and crop issues.

In a first for the IPCC, the report recommends looking to indigenous communities for ways to surmount those looming challenges. “Agricultural practices that include indigenous and local knowledge can contribute to overcoming the combined challenges of climate change, food security, biodiversity conservation, and combating desertification and land degradation,” the authors write.

The report’s author team consists of 107 experts from 52 countries, with dozens of contributing authors assisting on a chapter-by-chapter basis. More than half of the authors are from developing countries, a first for the IPCC. The land report will be followed by a second report in September that looks at climate change and oceans, along with the cryosphere (water in solid forms like ice).

Thursday’s release follows last year’s landmark report from the IPCC which estimated that the world had approximately 12 years left before crossing a critical threshold of global warming, one that would yield climate impacts on a scale not yet seen. With 11 years now left, the new report looks more closely at a likely coming food crisis and the role of land use as both perpetrator and savior.

“Land is where we live. Land is undergoing human pressure and is part of the solution, but land can not do it all,” IPCC housing chair Hoesung Lee said in a Thursday morning press conference.

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Climate impacts are already taking a severe toll on land, with heat waves and droughts undermining food security along with human health and the environment, the IPCC’s latest report explains.

If the Earth passes 1.5 degrees Celsius above preindustrial temperatures, wildfires will also become an even bigger threat. And if the world passes 2 degrees Celsius of warming — the upper threshold established in the Paris climate agreement — a food crisis becomes highly likely, the report warns, with developing countries most likely to suffer.

The land report also singles out several other key areas of concern, including deforestation, particularly in tropical rainforests. The Amazon is one of the world’s major carbon sinks, playing a critical role in undercutting rising temperatures. But Brazilian President Jair Bolsonaro has opened up the Amazon to major deforestation efforts, sparking alarm from experts.

Desertification also poses a serious threat, with half a billion people already living in areas that are turning into desert, and soil being lost as much as 100 times as fast as it is gained.

The IPCC’s findings echo a major report released in July by the World Resources Institute (WRI) and other international organizations. That analysis probed how to feed 10 billion people by mid-century while using significantly less land, reducing emissions, and accounting for equitable food and nutrition access.

Like the IPCC, that report concluded that people would need to embrace plant-based diets and shift away from meat, while also potentially embracing crop modification through technology like CRISPR, which can be used to edit genomes.

The IPCC’s findings lend weight to lawmakers backing dramatic climate action like the Green New Deal resolution, an ambitious plan introduced in February by Rep. Alexandria Ocasio-Cortez (D-NY) and Sen. Ed Markey (D-MA). That blueprint for rapidly zeroing out emissions across the United States has drawn fire from Republicans, many of whom argue it would “ban meat.” The proposal itself does not call for such steps, but it does underscore the agricultural changes likely necessary for net-zero emissions.

And farming has already found its way into the 2020 race. Sen. Elizabeth Warren (D-MA) on Wednesday released a “new farm economy” plan, one that would seek to empower small farmers over agribusinesses while encouraging climate-friendly practices. “[T]he agriculture sector has become one of the largest polluters in our economy,” Warren argues in her proposal.

Warren isn’t alone. Sens. Kirsten Gillibrand (D-NY) and Amy Klobuchar (D-MN) have also released agriculture plans with environmental angles. And Sen. Cory Booker (D-NJ) on Thursday released his own Senate plan for a “nature-based” strategy that would put billions of dollars into encouraging ranchers and farmers to reduce emissions through green practices.